Erguel Castle (Ruin) (Sonvilier)

The construction dates of the Château d'Erguël are not known. It seems true that in the 11th century, the d'Erguël (or d'Arguel) family, originally from Franche-Comté, settled in the castle to exercise the function of bailiff until 1264. Of this building, which formerly consisted of a double main building, a small building with a courtyard, and a square tower leaning against a watchtower, today only the lower part of the watchtower and one side of the tower remain. Some wall remnants can also be seen.

In 1284, Prince-Bishop Henri d'Isny undertook important restoration work. In 1386, it was partially burned down. In 1617, restorations were considered by the bishop. The most urgent repairs were carried out, but new destructions occurred, attributable to the Thirty Years' War. From the beginning of the 18th century, the maintenance of the castle was abandoned. The buildings gradually fell into ruin. Restorations were requested by the Société jurassienne d'Emulation between 1928 and 1930, and some work was carried out in 1964. In 1997 and 1998, the watchtower and part of the building were cleared.